---
title: "Helpers and constants"
description: "What else the package defines besides the client’s methods."
url: "https://openemail.uk/docs/csharp/reference/helpers"
area: "C#"
category: "Reference"
---

# Helpers and constants

What else the package defines besides the client’s methods.

## Helpers

| Helper | What it is |
| --- | --- |
| `new OpenEmailClient()` | A client. It reads the environment for anything you leave out, and throws `ArgumentException` for a configuration it refuses. |
| `OpenEmailClient.CreateTempMail()` | A client for disposable inboxes that carries no API key. |
| `OpenEmailClient.VerifyWebhookSignature()` | Checks the signature of a delivery in constant time, with a five minute window that `toleranceSeconds:` changes, and returns the event. |
| `OpenEmailClient.IsApiKey()`, `OpenEmailClient.IsAccessToken()` | Whether a value has the shape of an API key or of an access token. |
| `OpenEmailClient.IsSealed()` | Whether a message is end to end encrypted, so its body cannot be read by the API. |
| `OpenEmailClient.ResolveLanguage()`, `OpenEmailClient.LanguageByCode()`, `OpenEmailClient.IsRtlLanguage()` | Look a language up by code, English name or own name, in the table `Languages.All` holds. |
| `OpenEmailClient.ToBase64()`, `OpenEmailClient.ToBase64Async()` | Encode a `byte[]` or a `Stream` as base64, for a field that takes base64 text. |
| `client.Raw.RequestAsync()` | Calls a path no method wraps yet, with the credential and retry policy of the client. |

## Types

| Type | What it is |
| --- | --- |
| `Body` | A request body: a dictionary with the field names of the API, sent in the order its keys were added. |
| `JsonObject` | A decoded response, from `System.Text.Json.Nodes`. Read a field with `sent["id"]`, and cast it with `(string?)sent["id"]`. |
| `Page` | One page of a list: `Items`, `HasMore` and `NextCursor`. |
| `BatchResult`, `TemplateSends`, `PeoplePage`, `TempMessagesPage`, `AddressBook`, `AddressBookPage` | The answers that hold more than a list, such as the `Sent` and `Failed` counts of a batch. |
| `OpenEmailApiException`, `OpenEmailNetworkException`, `OpenEmailWebhookException` | What the client throws. All three derive from `OpenEmailException`. |

## Constants

The `OpenEmail.Constants` namespace holds every set of values the API uses, generated from the TypeScript SDK: webhook events, scopes, statuses and the rest. Each set is a static class whose members are constants, and `Values` lists them all.

**constants.cs**

```
using OpenEmail.Constants;

var webhook = await client.Webhooks.CreateAsync(new Body
{
    ["url"] = "https://example.com/webhooks/openemail",
    ["events"] = new[] { WebhookEvents.EmailReceived, WebhookEvents.EmailBounced },
});

Console.WriteLine($"{webhook["id"]} {WebhookEvents.Values.Count}");
```